Methods of producing regenerated cellulose



United States.

of production invarious respects.

3,232,779 METHODS OF PRODUCING REGENERATED CELLULOSE Nikolaus Augustin Schiinfeldt, Molndal, and Kurt Helmut Grunewald, and Olof Rune Steijner, Goteborg, Sweden,

assignors to M Och Domsjii Aktiebolag, Ornskiildsvik, Sweden, a corporation of Sweden No Drawing. Filed Nov. 20, 1959, Ser. No. 854,219 Claims priority, application Sweden, Jan. 20, 1955, 3

5 Claims. (Cl. 106-165) Regenerated cellulose is produced by converting cellulose to a soluble compound thereof and in a subsequent step reforming the cellulose. The most widely used process of producing regenerated cellulose is the viscose process in which the cellulose is converted to cellulose xanthate. Briefly described, this process comprises mercerizing cellulose with caustic soda to produce alkali cellulose. After squeezing out excess soda, the alkali cellulose is comminuted in a mill and is then stored for a period of time to undergo aging. Thereupon, carbon disulfide is introduced whereby cellulose xanthate is formed. The cellulose xanthate is dissolved in dilute alkali to form a viscous solution called viscose. The viscose is filtered and stored for a few days whereupon it is extruded through fine holes in spinnerets into a spinning bath, which usually comprises sulfuric acid and various salts. Thereby, the viscose is coagulated and solidified with reformation of the cellulose in the form of filaments or fibers, which are subjected to washing and other treatments and is then dried. The viscose may also be extruded through dies adapted to form films,

whereby the regenerated cellulose will be obtained in by the cuprammonium process, which is similar to the viscose process, but uses a solution of cuprammonium hydroxide to dissolve the cellulose. The processes of producing regenerated cellulose are well-known and de scribed in the technical and patent literature, and will not be described in detail here.

In various steps of the production of regenerated cellulose various substances are used as additives. These serve the purpose of facilitating and improving the process Depending on which object the additives have to fulfill, they may be entirely different in their chemical constitution and properties. The additives are used for example to improve the filtering characteristics of the viscose, to prevent yarn milkiness, to reduc the gel swelling during the spinning or as anti-clogging agents or as finishing agents (avivage agents) to soften the finished fiber, etc. Additives are used not only in the production of viscose rayon but also in the productionof cuprammonium rayon. I

Generally, different products are used in difierent steps of the production process and consequently their solubility in the viscose or in the spinning bath may be quite different. If the product is added to .the viscose it is desirable that the substance in question dissolves clearly therein. If the product is added to the spinning bath it is advantageous if it dissolves clearly or is finely dispersed therein. It is frequently tound that products which are added to the viscose are not sufficiently soluble in the spinning bath and vice versa. It would of course be Patented Feb. 1, 1966 highly advantageous to be able to employ products which are soluble or dispersible both in theviscose and in the spinning bath and thereby can beneficially influence the process of production. It on the other hand, the agents are used to soften rayon silk or rayon staple fibers as such or in combination with other substances, it is important that finely dispersed emulsions can be used so that when ing of the fibers occurs evenly.

A further circumstance which is to be considered is the chemical resistance of the additives in various stages of the process. When adding it prior to spinning, it will be subjected to alkalies, in the spinning bath it is exposed to sulfuric acid and to salts at an elevated temperature. If the agent in question is resistant to alkali, but is attacked in the spinning bath by sulfuric acid or the salts' present in the spinning bath, precipitates may be formed which may affect the spinning process adversely. In addition the action of the spinning bath becomes still stronger in the evaporation of the spinning bath, which often takes place at 80 or higher temperatures, so that decompositions of the additives may occur, which may in which R represents hydrocarbon radical having from 6 to 22 carbon atoms, x is l to 5, and z is 2 to 3. The compounds used according to this inventon are ethylene oxide and propylene oxide adducts of said polyamines, wherein the number of ethylene oxide or propylene oxicle units is from 1 to 10. These compounds are used in amounts ranging from 0.1 to 4% by weight based on the cellulose.

The radical R may be, e.g., an "aliphatic straight-chain or branched-chain, saturated or unsaturated hydrocarbon grouping. Representative examples include ethylhexyl, d-odecyl, hexadecyl, octadecenyl and octade-cyl groups. Furthermore, R may be an aryl or alkylaryl or aralkyl group. benzene and nonylnaphthalene groups.

Compounds of the above type may be obtained by cond'ensing an appropriate polyamine (such as, e.g., ethylene diarnine, diethylene triamine, triethylene tetram-ine, dipropylene triamine, ethyl dipropylene triamine etc., or mixtures of such polyamines) with a compound containing the radical R linked to a reactive group, such as halogen, and then condensing the substances thus obtained with an alkylene oxide, such as ethylene oxide or propylene oxide to introduce into the compound one or more alkylene oxide units per mole of the compound. Since the nitrogen atoms of the resulting compounds are linked only to carbon atoms, these compounds are chemically very resistant even after addition of the alkylene oxide.

By a suitable choice of the hydrocarbon radical R, of

. the number of nitrogen atoms equal to or above 2 and the number of alkylene oxide units per mole of compound it is possible to prepare substances which are most suitable as additive either in the production or in the finishing of the regenerated cellulose. The above mentioned possibilities of varying the composition permit, in

addition to a suitable adaptation of functional properties the preparation of compounds having good solubility and dispersibility characteristics in various stages of the process of producing regenerated cellulose.

If the compounds are to be used as finishing agents the radical R in the above formula should preferably be Examples include dodecyl-benzene, octadecyla saturated group comprising 12-22 carbon atoms, and more preferably 18-22 carbon atoms, the number of nitrogen atoms should preferably be within the range of from 2 to 4 (x=l to 3) and the polyglycol residue should preferably be relatively short, e.g., from 1 to 6 alkylene oxide units.

If the compounds are to be used as additives in various stages of the production, e.g., be added to the spinning 'bath or the viscose or even earlier in the process, the

radical R contains preferably 12-22 carbon atoms, more preferably 18-22 carbon atoms, and may advantageously be an unsaturated group, the number of nitrogen atoms should preferably be within the range of from 2 to 6 (x=1 to 5) and the polyglycol group should preferably be relatively long and contain 6 to 10, e.g., 8 alkylene oxide units.

Experiments have proved that, e.g., a compound of the above type, in which R was an octadecenyl group,

' transmission of 100% and this transmission of light decreases in 3 minutes to 50%, this period may be increased to about 30 minutes, i.e. about 10 times, by adding 1 g. of the above compound.

Compounds of the above formula may exhibit marked surface-active properties, resulting in a decrease in the surface tension of the viscose and the spinning bath. By varying the radical R, the polyamines used and the amount of ethylene oxide, the surface tension reduction can be kept within suitable limits.

In compounds of the above type, at least one of the nitrogen atoms can be quaternized by treatment with, e.g., dimethyl sulfate, diethyl sulfate, ethyl chloride etc. The compounds can also be condensed with formaldehyde or acetic anhydride to increase their stability to light. Quaternized compounds as well as such formaldehyde and acetic anhydride condensation products are within the ambit of this invention.

The amount of additive to be employed in the production of regenerated cellulose can vary to a relatively large extent. In the case of adding it in the mill, an amount of 0.1 to 0.4% based on the weight of cellulose, is often sufficient, in the case of adding it tothe viscose, preferably 0.3 to 0.5 g./l. will be used. As an additive to the spinning bath, it is customary to use 1 to 4 gs. per kg. of fiber. As an all skin agent an addition of 1 to 3 gs. per liter of viscose is advantageous. The term all skin agent (also called greening agent) denotes a substance, the action of which is that the fiber throughout its cross-section is imparted the properties which normally are present in its surface (skin). Such additives reduce the gel swelling. When softening regenerated cellulose, an amount of softening agent, in the case of rayon staple fiber, of 0.4 to 0.5%, and in the case of rayon filaments 0.7 to 0.8% is often advantageous.

The substance of the present invention may be used in the form of the pure compounds, but it is also possible to employ mixtures containing two or more compounds of the above formula.

The invention is illustrated but not limited by the following examples:

Example 1 1 mole of keryl chloride obtained by chlorination of kerosene is reacted at 150 to 160 C. with 1.2 moles of diethylene triamine whereupon the product is condensed with 8 moles of ethylene oxide, 2 gs. of this product per 4 kg. of finished yarn added to the spinning bath improves the spinning properties (e.g., less slubbing, prevention of spinneret incrustation) considerably.

Example 2 One mole of cocoa fat chloride obtained from cocoa fat alcohol by replacing the hydroxyl group by chlorine, is

reacted with 5 moles of ethylene diamine under reflux in Example 3 204 gs. of dodecyl chloride 15 reacted at 160 C. with 200 gs. of polyethylene polyamines obtained as distillation residue after distilling off diethylene triamine and triethylene tetramine from a polyethylene polyamine mixture obtained by reaction of ethylene dichloride and ammonia. The reaction is complete after 3 hours. The resulting product is condensed with 6 moles of ethylene oxide, 1 g. of this product per liter of viscose reduces swelling of the gel fiber.

Example 4 Keryl benzene is reacted in a known manner with formaldehyde and gaseous hydrogen chloride in the presence of zinc chloride to form kerylphenyl chloride. 500 parts by weight of this substance are reacted with 200 parts by weight of polyamines in accordance with Example 3. Thereupon 10 moles of ethylene oxide are condensed with the resulting product. An addition of 0.5 g. per liter of spinning bath improves the extrusion of the viscose and prevents the spinneret incrustation.

As above stated, compounds of the above types can be I quaternized, e.,g., with dimethyl sulfate, ethyl chloride, benzyl chloride etc. They can also, if desired, be treated with formaldehyde or acetic anhydride especially if the product is to be used as a finishing agent, in order to improve their resistance to light. Thereby formyl or acetyl groups are linked to certain of the nitrogen atoms. As

examples of such agents, the following may be men- V tioned.

Example 5 1 mole of octadecyl chloride is condensed with 4 moles of dipropylene triamine at 155 C. for 5 hours. Thereupon 1 mole of sodium hydroxide is introduced, whereupon excess of dipropylene triamine is distilled off. The octadecyl dipropylene triamine is then reacted with 2 moles of ethylene oxide. Thereupon the product is reacted with 1 mole of acetic acid anhydride at elevated temperature. If rayon fiber is softened with this product, the properties in the subsequent spinning and weaving steps can be substantially improved.

Example 6 1 mole of dodecyl tetraethylene pentamine is condensed with 6 moles of propylene oxide. 5 gs. of this product per liter of bath are used to soften rayon staple fiber.

Example 7 1 mole of 9,10-octadecenyl chloride is reacted at C. with 4 moles of triethylene tetramine. When the reaction is completed, 1 mole of sodium hydroxide is added to neutralize the hydrogen chloride formed, whereupon excess of triethylene tetramine is distilled off, suitably under vacuum. After separating sodium chloride precipitated 5 moles of ethylene oxide are reacted with the product. The 9,10-octadecen yl triethylene tetramine polyethylene polyglycol ether is then quaternized with 2 moles of di methyl sulfate. 0.4 g. of this product per liter of viscose improves the filtering properties.

What we claim is:

1. A process for producing regenerated cellulose from cellulose which includes the step of using as an additive, in any stage of the process, an amount within the range from about 0.1 to about 4% by weight, based on the cellulose, of a compound selected from the group consisting of (l) the reaction product of (a) from about one to about .ten moles of an alkylene oxide having from two to three carbon atoms with (b) one mole of at least one polyamine having the formula:

in which R is a hydrocarbon radical having from about six to about twenty-two carbon atoms, 2 is an integer from 2 to 3, and x is a number from 1 to 5; (2) reaction products of (l) a quaternizing agent selected from the group consisting of lower alkyl and benzyl quaternizing agents; and (3) reaction products of (1) with a member selected from the group consisting of formaldehyde and acetic anhydride.

2. A process for producing regenerated cellulose from cellulose which includes the step of using as an additive, in any stage of the process, an amount within the range from about 0.1 to about 4% by weight, based on the cellulose, of the reaction product of (a) from about one to about ten moles of an alkylene dioxide having from two to three carbon atoms with (b) one mole of at least one polyamine having the formula:

z 2z] x 2 in which R is a hydrocarbon radical having from about six to about twenty-two carbon atoms, z is an integer from 2 to 3, and x is a number from 1 to 5. 3. A viscose spinning solution containing from about 3% to about 4%, based on the weight of the cellulose in the viscose, of a modifier corresponding to the formula R (onlmo) ,11

NomotnomN ruoumno) x (o n 2nO 1H wherein R is a fatty alkyl hydrocarbon chain having between 8 and 18 carbon atoms, n is a Whole number of at least 2 but not greater than 3, x, y and z are whole numbers and the sum of x, y and z is about 10.

d. A viscose spinning solution containing from about 0.1 to about 4% by weight of the cellulose in the viscose of a modifier selected from the group consisting of (1) the reaction product of (a) from about one to about ten moles of an alkylene oxide having from two to three carbon atoms with (b) one mole of at least one polyamide having the formula:

R-[NHC H -NH;

in which R is a hydrocarbon radical having from about six to about twenty-two carbon atoms, z is an integer from 2 to 3, and x is a number from 1 to 5; (2) reaction products of (1) with a quaternizing agent selected fromin which R is a hydrocarbon radical having from about six to about twenty-two carbon atoms, 2 is an integer from 2 to 3, and x is a number from 1 to 5.

References Cited by the Examiner UNITED STATES PATENTS 2,593,466 4/1952 MacLaurin et a1. 106-165 2,674,619 4/ 1954 Lundsted -260-584 2,759,975 8/1956 Chiddix et al. l06----165 2,792,281 5/1957 Castellan 106-165 2,852,333 9/1958 Cox et a1. 106165 MORRIS LIEBMAN, Primary Examiner. JOSEPH R. SPECK, Examiner.

A. LIEBERMAN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,232,779 February 1, 1966 Nikolaus Augustin sch dnfeldt et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 16, for "mort read more column 2, line 64, for "additive" read additives column 3, line 28, for "intial" read initial line 64, for "substance" read substances column 5, line 29, for "dioxide" read oxide Signed and sealed this 31st day of January 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

4. A VISCOSE SPINNING SOLUTION CONTAINING FROM ABOUT 0.1 TO ABOUT 4% BY WEIGHT OF THE CELLULOSE IN THE VISCOSE OF A MODIFIER SELECTED FROM THE GROUP CONSISTING OF (1) THE REACTION PRODUCT OF (A) FROM ABOUT ONE TO ABOUT TEN MOLES OF AN ALKYLENE OXIDE HAVING FROM TWO TO THREE CARBON ATOMS WITH (B) ONE MOLE OF AT LEAST ONE POLYAMIDE HAVING THE FORMULA: 